Çevirimiçi Alışverişteki Engeller: Cinsiyet ve İnternet Güvenliğinin Etkileri

In the latest technology era, the widespread usage of internet enabled individuals tointeract continuously and led to altered buying behavior patterns. Literature focuses onthe critical effects in the field. Among many antecedents to online shopping, previousstudies point out two important obstacles: (i) acceptance and tendency to usetechnology in accordance with gender perceptions and (ii) internet security problems.This study analyzes the impact of these two prominent factors on e-commerce utilizationby studying the effects of these factors through primary and secondary data; a surveydesigned specifically for this analysis and the cross-country data from Eurostat. Thefindings show that while internet security problems significantly impact online shoppingbehavior, the evidence is mixed for the impact of gender. The results of this paperprovide insights for a successful e-commerce transaction and identify importantobstacles to be avoided for an efficient e-commerce system. Güncel teknoloji çağında, internetin yaygın kullanımı bireylerin sürekli etkileşim içindeolmasını sağlamış ve farklı alışveriş davranışlarına yol açmıştır. Literatürdekiçalışmalar, bu alandaki önemli etkileri ortaya çıkarmaya odaklanmıştır. Bu bağlamda,çevrimiçi yapılan alışverişi etkileyen unsurlar arasında iki önemli engel göze çarpmaktadır: i) Cinsiyet algısına bağlı teknolojiyi kabul etme ve kullanma eğilimi veii) İnternetteki güvenlik sorunları. Bu çalışma, göze çarpan bu iki unsurun e-ticaretinkullanımına olan etkilerini Eurostat'ın ülkeler arası verisini kullanarak ve de buçalışma için özel olarak tasarlanmış bir anketin sonuçlarını analiz ederekincelemektedir. Bulgular, internetteki güvenlik sorunlarının çevrimiçi alışverişdavranışını oldukça etkilediğini göstermektedir. Cinsiyetin etkileri ise daha karmaşıktır.Bu çalışmanın sonuçları başarılı bir e-ticaret işlemi için gerekenler hakkında fikirvermekte ve verimli bir e-ticaret sistemi için kaçınılması gereken önemli engellerigöstermektedir

Assessment of the dynamic stability of the portals of the Dorukhan tunnel using numerical analysis

Instability problems may arise during the construction and operation of tunnels depending on the quality of the rock mass. In particular, determining instability problems at the portals of a tunnel is of utmost importance during excavation and operation of the tunnel. Slope instability and rockfalls are the most frequent instability problems that may be encountered at tunnel portals. Such instability problems can be triggered by dynamic effects such as earthquakes, blasting, etc. This study investigates the stability of the portals of the Dorukhan Tunnel connecting the provinces of Zonguldak and Bolu in the close vicinity of the North Anatolian Fault Zone (NAFZ), which is a well-known strike-slip 1500. km long fault. The effect of an earthquake that may occur in the NAFZ on the extent of failure has also been studied by numerical analyses. In the analyses, a three-dimensional dynamic analysis computer code, based on the finite difference method, has been used. According to results of the dynamic numerical analyses, the Devrek portal was found to be more stable than the Mengen portal. Moreover, it was found that, for acceleration values of dynamic wave higher than 0.5. g, tunnel portal slopes and the areas as far as 20-50. m from the tunnel entrance may suffer serious damage. Wave propagation perpendicular to the tunnel axis was established to cause more damage around the openings and in the portal slopes as wave compared to propagation parallel to the tunnel axis. © 2010 Elsevier Ltd

Pseudo seismic and static stability analysis of the Torul dam

Dams have a great importance on energy and irrigation. Dams must be evaluated statically and dynamically even after construction. For this purpose, Torul dam built between years 2000 and 2007 Harsit River in Gümüşhane province, Turkey, is selected as an application. The Torul dam has 137 m height and 322 GWh annual energy production capacity. Torul dam is a kind of concrete face rock fill dam (CFRD). In this study, static and pseudo seismic stability of Torul dam was investigated using finite element method. Torul dam model is constituted by numerical stress analysis named Phase2 which is based on finite element method. The dam was examined under 11 different water filling levels. Thirteenth stage of the numerical model is corresponding full reservoir condition which water filled up under crest line. Besides, pseudo static coefficients for dynamic condition applied to the dam in fourteenth stage of the model. Stability assessment of the Torul dam has been discussed according to the displacement throughout the dam body. For static and pseudo seismic cases, the displacements in the dam body have been compared. The total displacements of the dam according to its the empty state increase dramatically at the height of the water level of about 70 m and above. Compared to the pseudo-seismic analysis, the displacement of dam at the full reservoir condition is approximately two times as high as static analysis. © 2019 Techno-Press, Ltd

Assessment of dynamic response and stability of an abandoned room and pillar underground lignite mine

National Institute of Disaster Management (NIDM);American Society of Civil Engineers (ASCE)12th International Conference on Computer Methods and Advances in Geomechanics 2008 -- 1 October 2008 through 6 October 2008 -- Goa -- 93907The authors have been involved with some abandoned mines in the Tokai Region of Japan and they have been investigating their performance and responses in the long term and during earthquakes. In this article, some examples of stability problems observed in areas of abandoned lignite mines during earthquakes are summarized. Two-dimensional model tests of abandoned room and pillar mines are described and vibration characteristics and instability modes are briefly presented. Ground amplification is investigated at abandoned mine sites by using a series of finite element analyses. In the remaining part of the article, three-dimensional elasto-plastic dynamic stress analyses are presented. In numerical solutions, analyses are performed by using harmonic ground motions. It is found that the ground motions with low amplitudes may also cause significant damage in the surrounding mass around the mine and ground surface, depending on rock mass properties

Stability Assessment of the Gökgöl Karstic Cave (Zonguldak, Turkey) by Analytical and Numerical Methods

Turkey has many cave formations and some caves are important tourist attractions. Theses caves have natural and historical characteristics that need to be investigated and protected. An important rock engineering topic is the identification of possible rock falls and collapses in caves that are open to the public and planning preventive measures. In this study, the locations and types of instability problems were identified along a section of 875 m of the Gökgöl cave in Zonguldak, Turkey. The main instabilities were identified as block falls controlled by discontinuities, rock block sliding, and flexural toppling. To obtain the intact rock and rock mass properties of the stratified limestone which is the host rock of the cave, field and laboratory studies were conducted. Stability assessments for four different sections inside the cave were carried out using numerical and analytical methods, and the results were compared. The results of the analyses revealed that some countermeasures and precautions must be implemented to increase the stability in some areas of the Gökgöl cave, especially those which have potential for regional failure. © 2015, Springer-Verlag Wien

A comparative study of the effect of in situ stress field on the stability of underground openings

ISRM International Symposium - EUROCK 1996 -- 2 September 1996 through 5 September 1996 -- -- 139512In this paper, stabilities of various underground openings are compared. For this purpose, the relative size of the overstressed zone occurring around the opening and the factors affecting the geometry of this region have been considered. Using an analytical solution and an empirical failure criterion, it has been possible to demonstrate the effects of opening geometry and in situ stress field on the expected stability. © 1996 Balkema, Rotterdam

A numerical study on the ground amplifications in areas above abandoned room and pillar mines and old longwall mines

ISRM International Symposium - EUROCK 2013 -- 23 October 2013 through 26 October 2013 -- -- 138846In this article, the authors present the outcomes of their studies on the dynamic characteristics of ground and amplification of ground motions above abandoned mines and discuss their implications. In addition to the effects of some parameters associated with extraction, some topographic effects on ground motions in areas with abandoned mines are also investigated and results are presented. It will be clearly shown that ground amplifications may be quite large on the abandoned mines where extraction is carried out by room and pillar technique or open-pit mines. The ground amplifications may be 3–5 times that at the base. Particularly these amplifications may be quite large particularly near steep cliffs. © 2013 Taylor & Francis Group, London

Assessments on the stability of natural slopes prone to toe erosion, and man-made historical semi-underground openings carved in soft tuffs at Zelve Open-Air Museum (Cappadocia, Turkey)

The Zelve Open-Air Museum, consisting of three valleys, is one of the oldest historical semi-underground settlements in the Cappadocia Region of Turkey which was designated as a World Heritage Site in 1985 by UNESCO. Particularly in the first valley, there are a lot of underground openings of different sizes carved in a soft tuff next to the valley cliffs used for cliff settlement in the past and several antique churches with some geo-engineering problems. In addition, steep natural slopes in this valley are prone to toe erosion resulting in stability problems. In this study, it is aimed to investigate engineering characteristics of the surrounding tuff and factors affecting them, and to assess the effect of rate of toe erosion on the stability of steep valley slopes and structural stability of some selected typical underground openings with large spans subjected to spalling. For these purposes, some observational, experimental and numerical modelling studies were conducted. Experimental results indicate that strength and deformability properties of the weak tuff surrounding the openings drastically reduce when it becomes wet or saturated. This situation suggests that possibility of occurrence of failures is expected to be higher in rainy seasons due to increase in water content of the tuff. Experimental results also suggest that spalling commonly observed in the valley is related with freezing-thawing and wetting-drying cycles in nature and that the process of freezing and thawing accelerates further the degradation of the rock. The long-term measurements at selected locations suggest that erosion in the tuff is important, which increases particularly in winter and spring seasons and results in the loss of support accelerating the occurrence of further slope failures. The 2-D numerical solutions indicate that no significant change in shear and tensile stresses in steep valley slopes prone to toe erosion would be expected after 100. years. However, the solutions obtained from the 500- and 1000-year scenarios suggest that failure zones due to the tensile stresses would develop in the form of slabs with thicknesses of 50-60. cm and 90-100. cm, respectively, which would break off from the slope and fall down. The results from 3-D numerical solutions indicate that failure (yield) zone resulting from tensile stresses around the semi-underground openings will develop parallel to the sidewalls. These results confirm the observed spalling of the tuff in the form of slabs parallel to the walls of the openings. © 2013 Elsevier B.V

Experimental studies on the dynamic response and stability of some historical masonry structures in ryukyu archipelago

8th Asian Rock Mechanics Symposium, ARMS 2014 -- 14 October 2014 through 16 October 2014 -- -- 118520The authors have been recently involved with the restoration of the various historical masonary structures as well as static and dynamic stability assessment of some natural monumental rock structures. Furthermore, dynamic limiting equilibrium methods (D-LEM) as well as numerical methods used for stability assessment of these structures. The outcomes of these studies are presented and their implications on the stability of historical masonary structures in Ryukyu Archipelago under dynamic loads such as those induced by earthquakes are discussed. © 2014 by Japanese Committee for Rock Mechanics

An integrated study on the response of an arch structure above karstic caves at New Ishigaki Airport

14th International Conference of International Association for Computer Methods and Recent Advances in Geomechanics, IACMAG 2014 -- 22 September 2014 through 25 September 2014 -- Kyoto -- 107391The authors have undertaken some studies on the stability assessment methods for natural underground openings in Ryukyu limestone in Ryukyu Islands and arch structures built above these caves to prevent any possible damage to the runway. The authors carried out a series of computations using 2D and 3D numerical methods to check the stability assessment of natural underground openings with its protection arch structure. In this article, the authors would present the outcomes of the numerical studies and discuss their implications. © 2015 Taylor & Francis Group, London