TOBB ETU GCRIS Database
Not a member yet
9778 research outputs found
Sort by
Roma Hukukundan Günümüz Hukukuna Işık Tutan İlkeler, Kavramlar ve Digesta Metinleri
No full text[No Abstract Available
Coverage and Connectivity Based Lifetime Maximization With Topology Update for Wsn in Smart Grid Applications
No full textThe self-sufficient Smart Grid (SG) with two-way data communication among its constituents is proposed as a remedy to the shortcomings of the traditional power grid. Due to their low cost and ease of deployment along with the advanced communication capabilities they offer, WSNs are seen as an important technology for SG applications. To this end, it is important to design energy-efficient communication protocols to achieve a long network lifetime while maintaining the desired coverage level. In this paper, we consider the case where the transmission paths are re-adapted to topology changes as long as the required coverage level and connectivity to the base station can be maintained with the current set of sensors with positive residual energy. We first propose a novel 0-1 mixed-integer programming (MIP) model, and then present two alternative 0-1 MIP models opti-mizing the network behavior in unit time decomposition with an emphasis on energy consumption. Our study is unique in terms of including topology adaptation due to energy depletion within a holistic solution framework based on optimization methods. We avoid the traditional time until the first sensor dies metric and allow the WSN to continue to function optimally as long as the predetermined coverage level and connectivity to the BS can be achieved with the remaining sensors. We observe that network lifetime can be increased significantly even after a one-time reorganization. Moreover, we analyze how the solutions of the three models differ in terms of lifetime and coverage level. As a side contribution, we show that maximizing the time until the first sensor dies is equivalent to minimizing the energy consumption of the most used sensor for the classical single-period problem, which is not necessarily true when there is an adaptation to a topology change. Hence, we provide a practical tool to determine the theoretical upper bound on the network lifetime with coverage and connectivity-based QoS requirements.TUBITAK [219M436]This work was supported by the TUBITAK Grant with project 219M436
Peptitlerin Altın (au) {111}-yüzeyi ile Etkileşimlerinin İncelenmesi
No full textProteins are known to have a role in mineral nucleation, growth, and structure creation, as well as providing molecular scaffolding for the formation of soft and hard tissues such as bone and dental tissues. Today in bionanotechnology, proteins and peptides are used in various fields such as biosynthesis, biosensors, drug delivery and targeting, integrated with inorganic materials (Ag, SiO2, TiO2, Pd, Pt, graphene, hydroxyapatite, etc.). Here, specific binding of peptides to materials affects device performance and this specifity is related to peptide sequences and structures. Today, these peptides are selected with inspration from nature or combinatorial selection methods. So, a deeper understanding of interactions between inorganic materials and peptides/proteins and design of peptides with desired specifity and properties is very important for the improvement of technology. Gold is a highly conductive inorganic and amenable to surface modifications. When gold is functionalized with peptides, it has practical applications such as bioimaging, biosensors, cancer therapy and drug delivery. In this research, we use atomistic methods (NAMD) to understand how peptides interact with Au {111}-surface. In this study, the binding mechanisms of well known peptides that binds to Au {111}-surface are found out. In addition, two peptides are designed via optimization of peptide sequences, binding structures and affinities to Au {111}-surface.Proteinler ve peptitler, doğada yaşam için gerekli olan, metabolik reaksiyonları katalize etme, DNA replikasyonu, moleküler taşınım, yumuşak ve sert doku (kemik, diş) oluşumu da dahil olmak üzere çok çeşitli hayati işlevler ve süreçlerde yer alırlar. Günümüzde, protein ve peptitler biyonanoteknolojide inorganik malzemeler (Ag, SiO2, TiO2, Pd, Pt, grafene, hidroksiapatit, vb.) ile bütünleşmiş bir şekilde, biyosentez, biyoalgılayıcılar, ilaç taşınımı ve hedeflenmesi gibi çeşitli alanlarda kullanılmaktadır. Burada, peptitlerin malzemelere spesifik olarak bağlanabilmeleri cihaz performanslarını etkilemektedir. Spesifik bağlanma peptitlerin amino asit sekanslarına ve dolayısı ile yapılarına bağlıdır. Günümüzde, inorganik malzemelere bağlanabilen peptitler doğadan esinlenerek ve/veya deneysel kombinatoryal seçim yöntemleri kullanılarak bulunmaktadır. Bu nedenlerle, inorganik malzemeler ile peptitler/proteinler arasındaki etkileşimlerin anlaşılması ve istenilen malzemeye özgü ve istenilen özelliklerde peptit/protein tasarımı teknolojik gelişim için çok önemlidir. Altın, iletken bir inorganiktir ve yüzey modifikasyonuna uygundur ve peptitlerle modifiye edildiğinde biyogörüntüleme, biyosensörler, kanser tedavisi ve ilaç taşınımı gibi pratik uygulamalarda kullanılabilir. Bu tez kapsamında, peptitlerin Au {111}-yüzeyi ile etkileşim mekanizmasını anlamak için atomistik modelleme yöntemleri (NAMD) kullanılmıştır. Yapılan çalışmalar ile altına bağlandığı bilinen peptitlerin bağlanma mekanizmaları ortaya çıkarılmış, buna ek olarak peptitlerin amino asit dizilimleri ve Au {111}-yüzeyleri ile bağlanma yapıları ve afiniteleri optimize edilerek peptit tasarlanmıştır
Kablosuz Sensör Aglarinda Yönlü Anten Kullanimi ve Uçtan Uca Gecikmeyi Kisitlamanin Farkli Performans Metrikleri Üzerindeki Etkisi
No full textWireless Sensor Networks (WSN), which have an important place in terms of wireless communication and the internet of things (IoT), are still up-to-date due to their various advantages and allow new potential workspace areas for the future. Due to limited battery life, optimization and energy efficiency are very important in the WSN. Although the current WSN can be used in many different areas, updates are needed for some special cases. The first of the special cases that are dealt with in this thesis is to be able to communicate with the low delay specified in the Ultra-Reliable Low- Latency Communication (URLLC) architecture, thus ensuring data freshness. To achieve the aforementioned situation in this thesis, it is recommended to restrict the delay or end-to-end (E2E) delay that is required for transmitting the data from each generator sensor to the base station. The second special case discussed in this thesis is to increase the performance for the places where the omnidirectional antennas in the WSN are insufficient. Since it is desired for a node to communicate with many nodes around it, an omnidirectional antenna is generally preferred as the antenna type for the WSN. On the other hand, the low bit error rates (BER) that are achieved in other communication systems cannot be achieved for this antenna type. In addition, due to the use of omnidirectional antennas, methods for dealing with interference between different nodes in the WSN are more limited and inefficient. Furthermore, unnecessary energy loss occurs due to communication within all directions for this antenna type. In order to overcome these problems in the second special case, the use of directional antennas is encouraged. Thanks to the use of the directional antenna, low bit error rates that cannot be reached in cases with omnidirectional antennas are achieved. Using a directional antenna also allows us to create more efficient methods by providing different working opportunities to get rid of the effect of interference. Limiting the E2E delay at this stage is also beneficial for creating more efficient methods. In addition to these, energy efficiency is also increased thanks to the possibility of communication in only a certain direction. Considering all these mentioned situations, four different studies are carried out for this thesis: In the first study, the effect of restricting the delay on the lifetime is examined while using only omnidirectional antennas. In this study, it is seen that restricting the delay has a negative effect on the lifetime. Furthermore, it is observed that increasing the number of nodes in the WSN also increases the lifetime. The second study examines the effect of restricting E2E delay on the lifetime and average BER. In the related study, the advantages of directional antennas are highlighted by using both omnidirectional and directional antennas for each scenario. In this study, it is observed that restricting the E2E delay not only reduces lifetime but also increases average BER. In addition, a large increase in the lifetime and a large decrease in average BER is observed while using directional antennas. In the third study, only directional antennas are used, but two different analyses are carried out. In the first analysis, the minimum E2E delay required for communication with a particular BER is calculated, considering the density of the sensor network. The second analysis examines the impact of restricting E2E delay and BER on the lifetime. In both analyses, very low BER values can be used for the restriction by taking advantage of the benefits provided by the directional antenna. As a result of this study, it is seen that as the number of nodes in the WSN increases, the minimum E2E delay required to reach a certain BER decreases. Additionally, it is seen that restricting BER decreases the lifetime like the E2E delay restriction. In the last study, considering the advantages of using directional antennas and limiting the E2E delay, two different methods are discussed to prevent interference. For the first of these methods, Time Division Multiple Access (TDMA), which is currently a popular method, is preferred. The second method is the Interference Preventing Model (IPM), which is designed for this thesis and makes more use of the advantages of directional antennas so that efficiency can be increased. Performance evaluation is made by comparing the bit rates and lifetimes that are calculated by using both methods. Accordingly, a higher bit rate is achieved by using IPM compared to TDMA. Moreover, in cases where IPM has the same bit rate as TDMA, there is an increase in lifetime.Kablosuz haberleşme ve Nesnelerin İnterneti'nde (IoT) önemli bir yere sahip olan Kablosuz Sensör Ağları (KSA), sağladıkları farklı avantajlar sayesinde güncelliğini korumakta ve gelecek için de potansiyel yeni çalışma alanlarının oluşmasına olanak sağlamaktadır. Pil ömrünün kısıtlı olduğu KSA'da optimizasyon ve enerji verimliliği son derece önem taşımaktadır. Günümüzde kullanılan KSA her ne kadar birçok farklı alanda kullanılabilse de bazı özel durumlar için güncellemelere ihtiyaç duyulmaktadır. Bu tez çalışmasında ele alınan özel durumların ilki, Ultra Güvenilir Düşük Gecikmeli İletişim (URLLC) mimarisinde de belirtilen düşük gecikmeyle haberleşme yapılabilmesi ve bu sayede veri tazeliğinin sağlanmasıdır. Bahsedilen durumu sağlayabilmek amacıyla bu tez çalışmasında, her bir sensörde üretilen verinin baz istasyonuna iletilmesi için gereken gecikmenin ya da uçtan uca gecikmenin (UUG) kısıtlanması önerilmektedir. Bu tezde ele alınan ikinci özel durum ise KSA'daki tümyönlü antenlerin yetersiz kaldığı yerler için performansın artırılmasıdır. KSA'da bir düğümün, çevresindeki birçok düğümle haberleşmesi istenildiği için anten tipi olarak genellikle tümyönlü anten tercih edilmektedir. Öte yandan ilgili anten tipinin seçilmesi yüzünden diğer haberleşme sistemlerinde erişilen düşük bit hata oranlarına (BER) ulaşılamamaktadır. Ayrıca tümyönlü anten kullanımdan ötürü, KSA'daki farklı düğümler arasındaki haberleşme sırasında meydana gelen girişimin üstesinden gelen yöntemler daha sınırlı ve verimsiz olmaktadır. Buna ek olarak ilgili anten ile bütün yönlerde haberleşme yapılması dolayısıyla gereksiz enerji kaybı meydana gelmektedir. İkinci özel durumda yer alan bu sıkıntıların üstesinden gelmek için yönlü anten kullanılması teşvik edilmektedir. Yönlü anten kullanımı sayesinde, tümyönlü antenli durumlarda erişilemeyecek düşük BER'e ulaşılması sağlanmaktadır. Yönlü antenin kullanmak bize girişimin etkisinden kurtulmak için farklı çalışma imkânları sağlayarak daha verimli yöntemlerin oluşturulmasına da olanak sağlamaktadır. Bu aşamada UUG'yi sınırlamak, daha verimli yöntemlerin oluşturulması için ayrıca faydalı olmaktadır. Bunlara ek olarak sadece belli bir yönde haberleşmeye olanak sağlanması sayesinde enerji verimliliği de artmaktadır. Bütün bu bahsedilen durumlar göz önüne alarak bu tez çalışması özelinde dört farklı çalışma gerçekleştirilmektedir: İlk çalışmada sadece tümyönlü anten kullanılarak gecikmeyi kısıtlamanın yaşam süresine etkisi incelenmektedir. Bu çalışmaya göre gecikmeyi kısıtlamanın yaşam süresi üzerinde negatif bir etkisi olduğu görülmektedir. Ayrıca KSA'daki düğüm sayısını artırmanın da yaşam süresini artırdığı görülmektedir. İkinci çalışmada UUG'yi kısıtlamanın yaşam süresi ve ortalama BER üzerindeki etkisi incelenmektedir. İlgili çalışmada her senaryo için hem tümyönlü hem de yönlü antenler kullanılarak yönlü antenlerin sağladığı avantajlar ön plana çıkarılmaktadır. Bu çalışmada UUG'yi kısıtlamanın yaşam süresini azaltırken ortalama BER'i de artırdığı gözükmektedir. Ayrıca yönlü anten kullanılan senaryolarda yaşam süresinde büyük artış gözlenirken BER'de de büyük düşüş gözlenmektedir. Üçüncü çalışmada sadece yönlü anten kullanılmakla birlikte iki farklı inceleme yapılmaktadır. İlk incelemede sensör ağı yoğunluğu göz önüne alınarak belli bir BER ile iletişimin gerçekleşebilmesi için gerekli minimum UUG hesaplanmaktadır. İkinci incelemedeyse UUG'yi ve BER'i kısıtlamanın yaşam süresi üzerindeki etkisi incelenmektedir. Her iki incelemede de yönlü antenin sağladığı avantajlardan yararlanılarak kısıt için çok düşük BER değerleri kullanılabilmektedir. Bu çalışma sonucunda KSA'daki düğüm sayısı arttıkça belli bir BER'e ulaşmak için gerekli minimum UUG'nin azaldığı görülmektedir. Ayrıca, UUG'nin yanı sıra BER'i kısıtlamanın da yaşam süresini düşürdüğü gözlenmektedir. Son çalışmada ise yönlü anten kullanımının ve UUG'yi kısıtlamanın bize sağladığı avantajlar göz önüne alınarak girişimi engellemek için iki farklı yöntem ele alınmaktadır. Bu yöntemlerin ilki için halihazırda popüler bir yöntem olan Zaman Bölmeli Çoklu Erişim (TDMA) tercih edilmektedir. İkinci yöntem ise bu tez için tasarlanıp yönlü antenlerin avantajlarından daha fazla yararlanan ve verimi artırmak için kullanılan Girişim Engelleyici Model'dir (GEM). Her iki yöntemin kullanılması sonucu hesaplanan veri hızı ve yaşam süresi karşılaştırılarak performans değerlendirilmesi yapılmaktadır. Buna göre GEM kullanılarak TDMA'e kıyasla daha yüksek veri hızına erişilmektedir. Ayrıca GEM'in, TDMA ile aynı veri hızına sahip olduğu durumlarda da yaşam süresinde artış meydana gelmektedir
A Study on Applications of Glocalization in Creative Industries
No full textThe painful transition process from modernism to postmodernism makes its impact felt in the field of globalization as well. Advances in technology have overcome the difficulties experienced in mass production and accessing global markets, enabling the integration of more local markets into the global economy. However, the rapid increase in participants made it difficult to compete in the global market, and the proliferation of different local markets caused cultural differences to become more evident. The study examines the contribution of creative industries and glocalization strategies to the resolution of the global-local conflict, by considering them together. In this study, the findings were analyzed by using the literature review and the survey method together. A total of 310 people, 145 men and 165 women, participated in the survey in Janury 2019. In the case of Turkey, the research shows that there is a positive correlation between the customer experience created by the global brand by considering the cultural, economic and political data of the local society and the level of ad appreciation
The Network Science, International Law, and Corporations: a Theoretical Framework for Corporate Accountability
No full textThe network science, used for analysing a wide range of physical, biological, and social phenomena, could be a guide in developing a global holistic and coherent model for sustainable and accountable businesses operating within the limits of planetary boundaries and respecting human rights. In theorizing and shaping a corporate human rights accountability mechanism, we can use 1) the social and organizational network analysis to understand the corporate organizational model and the actors of the global governance network, and 2) the legal network analysis to demonstrate the reflection of these social and organizational phenomena in the legal web of international, regional, and national regulatory regimes. The new model of international governance network designed for ensuring an effective corporate accountability mechanism, may be reimagined and organized as a ‘glocal’ network of networks. This international network would consist of formal and informal, vertical and horizontal, regional and national interconnected sub-networks operating through interactive communication and consultation processes among all relevant public and private stakeholders. In this article, the ongoing work of the Open-ended intergovernmental working group on transnational corporations and other business enterprises with respect to human rights, on establishing an accountability mechanism under the Draft Business and Human Rights Treaty and its Draft Optional Protocol, is analysed through the lens of the network theory in order to demonstrate that the envisaged institutions under these draft documents and their functioning strategies can be conceptualized and further developed based on the theories and methods of network science
Effects of Melatonin and Doxorubicin on Primary Tumor and Metastasis in Breast Cancer Model
No full textBackground: Melatonin exerts oncostatic effects on breast cancer via immunomodulation and anti-oxidation. Doxorubicin is an effective chemotherapeutic agent, but parallel studies also provide ample evidence of an off-target effect of Doxorubicin in breast cancer patients. Objective: Combinatorial use of doxorubicin and melatonin has not been comprehensively analyzed in breast cancer models. We hypothesized that the anti-oxidative, anti-proliferative and anti-inflammatory effects of melatonin could ameliorate the off-target effects of doxorubicin in breast cancer patients and enhance the anti-tumoral effects of doxo-rubicin. The goal of the study is to test this hypothesis in cancer cell lines and xenografted mice. Methods: The effects of Melatonin and doxorubicin on the cell viability were evaluated in 4T1-Brain Metastatic Tumor (4TBM). Furthermore, the effects of melatonin and doxorubicin on the primary tumors and systemic metastasis were evaluated in the xenografted mice. Lung and liver tissues were removed and metastasis analyses were performed. The levels of p65, phospho-STAT3, CD11b+, GR1+, Ki67, and cleaved caspase-3 proteins were determined with im-munohistochemistry and western blot analysis. We examined the effects of melatonin and Melatonin+Doxorubicin combination therapy on 4TBM cells. Results: Our results showed that doxorubicin inhibited the proliferation of metastatic breast cancer cells while melato-nin did not affect cells. Tumor growth and metastasis were markedly suppressed in melatonin alone and in combination with doxorubicin. The expression of CD11b+ and GR1+ proteins, which are indicators of myeloid-derived suppressor cells (MDSCs), were noted to be reduced in both primary tumor and metastatic tissues in melatonin and doxorubicin groups. Conclusion: The combination of melatonin with doxorubicin reduced primary tumor growth and distant metastasis. Based on these results, melatonin is a promising candidate for combinatory use with conventional chemotherapeutics for breast cancer treatment. © 2022 Bentham Science Publishers.This study was funded by TUBITAK 3001. The Scientific and Technological Research Council of Turkey (Project number 315S181).The author acknowledge the financial support by TUBITAK 3001 The Scientific and Technological Research Council of Turkey.Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITAK: 300
Menu Optimization for Multi-Profile Customer Systems on Large Scale Data
No full textEveryday, a majority of the people, most probably several times, use the banking applications through online applications or physical ATM (Automated Teller Machine) devices for managing their financial transactions. However, most financial institutions provide static user interfaces regardless of the needs for different customers. Saving even a few seconds for each transaction through more personalized interface design might not only result in higher efficiency, but also result in customer satisfaction and increased market share among the competitors. In ATM Graphical User Interface (GUI) design, transaction completion time is, arguably, one of the most important metrics to quantify customer satisfaction. Optimizing GUI menu structures has been pursued and many heuristic techniques for this purpose are present. However, menu optimization by employing an exact mathematical optimization framework has never been performed in the literature. We cast the ATM menu optimization problem as a Mixed Integer Programming (MIP) framework. All the parameters of the MIP framework are derived from a comprehensive actual ATM menu usage database. We also proposed two heuristic approaches to reduce the computational complexity. Our solution can be accustomed with ergonomic factors and can easily be tailored for optimization of various menu design problems. Performance evaluations of our solutions by using actual ATM data reveal the superior performance of our optimization solution
Search for New Phenomena in Three- or Four-Lepton Events in Pp Collisions at Root S=13 Tev With the Atlas Detector
No full textA search with minimal model dependence for physics beyond the Standard Model in events featuring three or four charged leptons (3l and 4l, l = e, mu) is presented. The analysis aims to be sensitive to a wide range of potential new-physics theories simultaneously. This analysis uses data from pp collisions delivered by the Large Hadron Collider at a centre-of-mass energy of root s = 13 TeV and recorded with the ATLAS detector, corresponding to the full Run 2 dataset of 139 fb(-1). The 3l and 4l phase space is divided into 22 event categories according to the number of leptons in the event, the missing transverse momentum, the invariant mass of the leptons, and the presence of leptons originating from a Z-boson candidate. These event categories are analysed independently for the presence of deviations from the Standard Model. No statistically significant deviations from the Standard Model predictions are observed. Upper limits for all signal regions are reported in terms of the visible cross-section. Crown Copyright (C) 2021 Published by Elsevier B.V
Visually-Guided Braking: the Optical Variables, Control Strategies and the Effect of Vehicle Dynamics
No full textThis study aims to investigate the effects of vehicle dynamics, such as the braking function, on the optical variables and control strategies used in visually-guided braking. The task used in the study was to slow down from a high speed to stop before reaching an obstacle in the path of motion. Given this task, humans exhibit two different behaviors: impulsive braking and continuously regulated braking. The results of Experiment 1 indicated that, when the braking function was nonlinear, the weak version of the constant tau strategy was used in impulsive braking. The brake was initiated when the optical variable tau reached a critical value. When the obstacle was far away, the critical tau value was 3.7 s. When the obstacle was close, the critical tau value was 2 s. The aim of Experiment 2 was to investigate continuously-regulated braking. Experiment 2 revealed that, when the braking function was nonlinear, the participants exhibited predominantly impulsive braking and used the weak version of the constant tau strategy. The critical tau value used when away from the obstacle was 3 s, while the critical tau value used when close to the obstacle was 1.5 s. Taken together, the results of the present study indicate that a nonlinear braking function reinforces impulsive braking and suppresses continuously-regulated braking