Seismic responses of base-isolated buildings: efficacy of equivalent linear modeling under near-fault earthquakes

Cenk Alhan,Murat Özgür 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.6

Design criteria, modeling rules, and analysis principles of seismic isolation systems have already found place in important building codes and standards such as the Uniform Building Code and ASCE/SEI 7-05. Although real behaviors of isolation systems composed of high damping or lead rubber bearings are nonlinear, equivalent linear models can be obtained using effective stiffness and damping which makes use of linear seismic analysis methods for seismic-isolated buildings possible. However, equivalent linear modeling and analysis may lead to errors in seismic response terms of multi-story buildings and thus need to be assessed comprehensively. This study investigates the accuracy of equivalent linear modeling via numerical experiments conducted on generic five-story three dimensional seismic-isolated buildings. A wide range of nonlinear isolation systems with different characteristics and their equivalent linear counterparts are subjected to historical earthquakes and isolation system displacements, top floor accelerations, story drifts, base shears, and torsional base moments are compared. Relations between the accuracy of the estimates of peak structural responses from equivalent linear models and typical characteristics of nonlinear isolation systems including effective period, rigid-body mode period, effective viscous damping ratio, and post-yield to pre-yield stiffness ratio are established. Influence of biaxial interaction and plan eccentricity are also examined.

A Computerized Method for Delay Risk Assessment Based on Fuzzy Set Theory using MS ProjectTM

Cenk Budayan,Irem Dikmen,M. Talat Birgonul,Aydın Ghaziani 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

In this paper, we present a computerized method as an add-in to MS ProjectTM for risk identification and estimation of delay. Adelay analysis ontology is incorporated so that the users can identify causes of delay at the activity level and assess frequency andimpact of risks using their previous experience, expertise and judgement. Testing and validation findings demonstrate that thesoftware is easy to use and gives reliable results. Decision-makers can use this software during risk identification and planning phasesto incorporate their judgment about potential risk sources that may lead to project delay. The outputs of the software make it easy fordecision-makers to understand the level of delay risk at the activity level, explore how criticality of activities may change underdifferent risk occurrence scenarios and estimate amount of delay. By utilizing the software, effective risk response and allocationstrategies may be formulated to mitigate the delay risk and communicate delay risk information between various project participants.

Spatio-temporal analysis of the COVID-19 pandemic in Türkiye: results of the controlled normalization

Cenk İçöz,İsmail Yenilmez 대한공간정보학회 2023 Spatial Information Research Vol.31 No.1

This study investigates the spatio-temporal structure of the pandemic in Türkiye during the normalization process. An analysis has been conducted based on spatial and space–time scan statistics of the province-based numbers of confirmed COVID-19 cases during the normalization process from February 27 to May 7, 2021. The clusters affected by regional application differences has determined. The increase in cases has been observed, and the risk classes that supported the spatial relationship have been determined. Positive spatial relationships have been observed. Moran I measurements have also directly overlapped with the developments in the timeline of the COVID-19 pandemic in Türkiye. Local Moran I analysis has shown the transition of clusters from different regions to others over time. According to the results, controlled normalization has not happened as expected and the increase in the number of cases eventually led to the start of a total lockdown. Spatial and spatio-temporal analysis may show how to respond to a potential new pandemic. Regulations that vary from region to region can be meaningless depending on the spatial interaction. Decision makers may benefit in the future from these analyses, which reveal the results of experience to control current worsening scenarios.

Is Activating Transcription Factor 3 Up-Regulated in Patients with Hypospadias?

Cenk Gurbuz,Selamettin Demir,Ebru Zemheri,Lutfi Canat,Mert Kilic,Turhan Caskurlu 대한비뇨의학회 2010 Investigative and Clinical Urology Vol.51 No.8

Purpose: Even though hypospadias is one of the most common congenital anomalies, the cause of hypospadias is largely unknown. With regard to molecular biology and microarray technology, it appears that hypospadias is potentially related to disrupted gene expression. Genomic analysis of hypospadiac tissue indicated a potential role for activating transcription factor 3 (ATF3) in the development of this anomaly. This study prospectively examined the expression of ATF3 in tissues from 20 children with hypospadias compared with 26 normal penile skin tissue samples from elective circumcision. Materials and Methods: Prepucial tissue was obtained from children who underwent repair of hypospadias for comparison with tissue samples from children who underwent elective circumcision. Skin specimens were evaluated for the expression of ATF3 protein by immunohistochemical staining. Results: Immunohistochemical staining for ATF3 in samples from children who underwent repair of hypospadias was significantly greater than in samples from children who underwent elective circumcision (80% vs. 11%, respectively; p<0.05). Conclusions: Our results indicate that ATF3 is up-regulated in the penile skin tissue of boys with hypospadias, which suggests a role for this transcription factor in the development of this abnormality.

Seismic isolation performance sensitivity to potential deviations from design values

Cenk Alhan,Kemal Hisman 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.2

Seismic isolation is often used in protecting mission-critical structures including hospitals, data centers, telecommunication buildings, etc. Such structures typically house vibration-sensitive equipment which has to provide continued service but may fail in case sustained accelerations during earthquakes exceed threshold limit values. Thus, peak floor acceleration is one of the two main parameters that control the design of such structures while the other one is peak base displacement since the overall safety of the structure depends on the safety of the isolation system. And in case peak base displacement exceeds the design base displacement during an earthquake, rupture and/or buckling of isolators as well as bumping against stops around the seismic gap may occur. Therefore, obtaining accurate peak floor accelerations and peak base displacement is vital. However, although nominal design values for isolation system and superstructure parameters are calculated in order to meet target peak design base displacement and peak floor accelerations, their actual values may potentially deviate from these nominal design values. In this study, the sensitivity of the seismic performance of structures equipped with linear and nonlinear seismic isolation systems to the aforementioned potential deviations is assessed in the context of a benchmark shear building under different earthquake records with near-fault and far-fault characteristics. The results put forth the degree of sensitivity of peak top floor acceleration and peak base displacement to superstructure parameters including mass, stiffness, and damping and isolation system parameters including stiffness, damping, yield strength, yield displacement, and post-yield to pre-yield stiffness ratio.

Double Facial Nerve Trunk Emerged from the Stylomastoid Foramen and Petrotympanic Fissure: A Case Report

Cenk Kilic,Yalcin Kirici,Murat Kocaoglu 대한의학회 2010 Journal of Korean medical science Vol.25 No.8

There are several studies concerning branches of the facial nerve, but we encountered less information about the trunk of the facial nerve in the literature. During the routine dissection of a 65-yr-old Caucasian male cadaver, double facial nerve trunk emerged from the stylomastoid foramen and petrotympanic fissure were encountered. Because of an extremely rare variation, we presented this case report. In addition this cadaver had two buccal plexuses. These plexuses and other branches were formed to structures like to polygon. These anatomic peculiarities were described, photographed and illustrated. Finally,magnetic resonance imaging was performed by using 1.5T scanner to this cadaver. The facial nerve trunk can be damaged during surgical procedures of the parotid gland tumours and submandibular region. Surgeons who are willing to operate on this area should be aware of the possible anatomical variations of the facial nerve trunk.

Knowledge, Attitude, and Behavior Levels of Postmenopausal Women about Osteoporosis

Cenk Aypak 대한골대사학회 2023 대한골대사학회지 Vol.30 No.4

Background: Osteoporosis can be delayed by providing accurate and adequate information to people at risk. Therefore, we aimed to determine the knowledge, attitude, and behavior levels of women in the postmenopausal period, which is the largest group at risk. Methods: The study was conducted in a tertiary Training and Research Hospital between 1 December 2018 and 1 May 2019 in 225 postmenopausal women who applied to the Family Medicine outpatient clinic and bone mineral density (BMD) outpatient clinics for BMD measurement or had previously had this measurement at least once. A questionnaire evaluating the knowledge, attitudes, and behavior levels related to osteoporosis was applied to all patients included in the study. Results: The mean age was 58.05±9.1 years. The median osteoporosis knowledge score was 7 out of 19 points. A total of 119 (52.9%) had low knowledge scores and 106 (47.1%) had higher knowledge scores. Of the individuals with high scores, 40 (37.7%) were smoking, 64 (60.4%) did not sunbathe, 89 (84%) did not consume the recommended daily amount of calcium, and 58 (54.7%) were not exercising in the recommended time. It was seen that those who were university graduates, who had previously learned about osteoporosis from a health professional, and who had a family history of osteoporosis had higher knowledge levels. Conclusions: Even in postmenopausal women who are aware that they are in the risk group and that they should have BMD, their knowledge, attitude, and behavior levels on osteoporosis were found to be quite low.

Hyperlipidemia Disrupts Cerebrovascular Reflexes and Worsens Ischemic Perfusion Defect

Ayata, Cenk,Shin, Hwa Kyoung,Dilekö,z, Ergin,Atochin, Dmitriy N,Kashiwagi, Satoshi,Eikermann-Haerter, Katharina,Huang, Paul L SAGE Publications 2013 Journal of cerebral blood flow and metabolism Vol.33 No.6

<P> Hyperlipidemia is a highly prevalent risk factor for coronary and cervical atherosclerosis and stroke. However, even in the absence of overt atherosclerosis, hyperlipidemia disrupts endothelial and smooth muscle function. We investigated the impact of hyperlipidemia on resting-brain perfusion, fundamental cerebrovascular reflexes, and dynamic perfusion defect during acute focal ischemia in hyperlipidemic apolipoprotein E knockout mice before the development of flow-limiting atherosclerotic stenoses. Despite elevated blood pressures, absolute resting cerebral blood flow was reduced by 20% in apolipoprotein E knockout compared with wild type when measured by [<SUP>14</SUP>C]-iodoamphetamine technique. Noninvasive, high spatiotemporal resolution laser speckle flow imaging revealed that the lower autoregulatory limit was elevated in apolipoprotein E knockout mice (60 vs. 40 mm Hg), and cortical hyperemic responses to hypercapnia and functional activation were attenuated by 30% and 64%, respectively. Distal middle cerebral artery occlusion caused significantly larger perfusion defects and infarct volumes in apolipoprotein E knockout compared with wild type. Cerebrovascular dysfunction showed a direct relationship to the duration of high-fat diet. These data suggest that hyperlipidemia disrupts cerebral blood flow regulation and diminishes collateral perfusion in acute stroke in the absence of hemodynamically significant atherosclerosis. </P>

Efficacy of extracorporeal shock wave therapy for pillar pain after open carpal tunnel release: a double-blind, randomized, sham-controlled study

( Mehmet Cenk Turgut ),( Gonca Saglam ),( Serdar Toy ) 대한통증학회 2021 The Korean Journal of Pain Vol.34 No.3

Background: Pillar pain may develop after carpal tunnel release surgery (CTRS). This prospective double-blinded randomized trial investigated the effectiveness of extracorporeal shock wave therapy (ESWT) in pillar pain relief and hand function improvement. Methods: The sample consisted of 60 patients with post-CTRS pillar pain, randomized into two groups. The ESWT group (experimental) received three sessions of ESWT, while the control group received three sessions of sham ESWT, one session per week. Participants were evaluated before treatment, and three weeks, three months, and six months after treatment. The pain was assessed using the visual analogue scale (VAS). Hand functions were assessed using the Michigan hand outcomes questionnaire (MHQ). Results: The ESWT group showed significant improvement in VAS and MHQ scores after treatment at all time points compared to the control group (P < 0.001). Before treatment, the ESWT and control groups had a VAS score of 6.8 ± 1.3 and 6.7 ± 1.0, respectively. Three weeks after treatment, they had a VAS score of 2.8 ± 1.1 and 6.1 ± 1.0, respectively. Six months after treatment, the VAS score was reduced to 1.9 ± 0.9 and 5.1 ± 1.0, respectively. The ESWT group had a MHQ score of 54.4 ± 7.7 before treatment and 73.3 ± 6.8 six months after. The control group had a MHQ score of 54.2 ± 7.1 before treatment and 57.8 ± 4.4 six months after. Conclusions: ESWT is an effective and a safe non-invasive treatment option for pain management and hand functionality in pillar pain.

ON POINTWISE 1-TYPE GAUSS MAP OF SURFACES IN E3 1 CONCERNING CHENG-YAU OPERATOR

김영호,Nurettin Cenk Turgay 대한수학회 2017 대한수학회지 Vol.54 No.2

In this paper, we study surfaces in {3-dimensional} Minkowski space in terms of {certain} {type of} their Gauss map. We give several results on these surfaces whose Gauss map $G$ satisfies $\square G= f(G+C)$ for a smooth function $f$ and a constant vector $C$, where $\square$ denotes the Cheng-Yau operator. In particular, we obtain classification theorems on the rotational surfaces in $\mathbb E^3_1$ with space-like axis of rotation in terms of type of their Gauss map concerning the Cheng-Yau operator.