The Assessment and Reduction of Motion Artifact in Dry Contact Biopotential Electrodes

The connecting interface between biopotential monitoring systems and the human body is the electrode. Conventional medical electrodes use gel to improve skin-electrode contact and glue to provide secure attachment of the electrode to the skin. However, this type of electrode is neither reusable nor user-friendly when implemented in wearable monitoring systems. For wearable monitoring systems, the best type of electrode to use, as seen from the point of view of user comfort and ease of use of the wearable system, is the un-gelled electrode. The un-gelled electrode foregoes conductive gel and attachment glue and instead uses body moisture and clothing pressure to provide contact and secure attachment. The drawback of un-gelled electrodes is that they are susceptible to the wearer’s movements, namely, to motion artifact.Solving the issue of motion artifact will improve signal quality and reliability for wearable systems and, due to integration and reusability, would reduce costs. These two factors, when combined, would enable the widespread use of wearable monitoring systems in both the medical context and the consumer-user context. One effect of this will be a reduction in load and costs on health care systems due to improved preventive monitoring and better monitoring of patients in the recovery and rehabilitation phase. A second effect, combined with the information exchanging channels between individuals, will be unforeseen developments in health science due to what can be called the crowdsourcing of some aspect of physical and mental health and fitness.This thesis aims to further state-of-the art wearable physiological monitoring by aiding motion artifact research and electrode design. To accomplish this aim, investigations into the programmable and repeatable generation of electrode movement in order to generate motion artifact, the effect of impedance current frequency on the relationship between skin-electrode interface impedance and electrode movement and motion artifact, the effect of using an electrode support structure and how its design affects the motion artifact, and the effects of garment parameters such as tightness are presented in this thesis.A system that generates known and programmable motion of the electrode under controlled circumstances was designed, tested, and after the verification of system functionality, used in subsequent investigations. The presented system generates accurate motion of the electrode and the electrode motion can be observed as both motion artifact and skin-electrode impedance changes.A real time impedance spectroscopy study of 24 impedance current frequencies between 25 Hz and 1 MHz was done on electrodes subject to accurately known motion generated by the designed system in order to find the impedance current frequencies most suited to motion artifact studies.During this research, a hypothesis was formed that states that an electrode with a structural design that restricts epidermis deformation by trapping the epidermis under the electrode area can reduce motion artifact. Different electrode support structures were designed in order to test this hypothesis. The electrodes with support structures were subjected to system-generated motion and the resulting data were analyzed for the verification of support structure functionality and the hypothesis.Electrodes that were supported by a tight garment-mimicking elastic straps were studied under subjectgenerated movement and at various clothing tightness levels. The same study was used to understand the effect of using padding between the garment and the electrode.The motion artifact generation system was seen to be successful in accurately generating electrode motion, thus motion artifact, which was programmable and repeatable. The electrode mounting force monitoring proved to be an important functionality as the mounting force was seen to affect the motion artifact.Skin-electrode impedance was found to correlate well with electrode motion in current frequencies between 17 kHz and 1 MHz. While the correlation between impedance and motion artifact was lower than the correlation between impedance and electrode motion, it was also highest in this frequency band.Electrode support structure design is seen to be an important factor to consider when designing the electrode, and the electrodes that came closest to fulfilling the design criteria of the hypothesis were the best functioning electrodes. The hypothesis is seen to be promising and electrodes that distributed skin deformation over a large area and/or restrict epidermis deformation were found to reduce motion artifact.In the presented studies, the pressures under those electrodes that were found to be the most effective in reducing motion artifact differed between experiments yet stayed in a range between 5 mmHg -36 mmHg (0.66 kPa – 4.80 kPa). A simple guideline is that the electrode should be attached firmly but not so firmly that it becomes uncomfortable. This guideline fitted well with the pressure levels found for each experiment.The presented Motion Artifact Generation and Assessment System can be used for research or commercial purposes, furthering the research on motion artifact and aiding in the successful design of motion artifact resilient electrodes. The issue of which are the best current frequencies to use to measure skin-electrode interface impedance in motion artifact research has been clarified. Possible means of reducing motion artifact at its origin by using structural electrode designs that restrict epidermis deformation is hypothesized and proven worthy of further research. The importance of garment design and guidelines for use are given and tightness recommendations presented. The thesis presents methodology for the furthering of the understanding of motion artifact and electrode design that will eventually make wearable monitoring systems widespread over a large range of applications and a large number of users

The modified post-earthquake damage assessment methodology for TCIP (TCIP-DAM-2020)

Chapter 5Post-Earthquake damage assessment has always been one of the major challenges that both engineers and authorities face after disastrous earthquakes all around the world. Considering the number of buildings in need of inspection and the insufficient number of qualified inspectors, the availability of a thorough, quantitative and rapidly applicable damage assessment methodology is vitally important after such events. At the beginning of the new millennia, an assessment system satisfying these needs was developed for the Turkish Catastrophe Insurance Pool (TCIP, known as DASK in Turkey) to evaluate the damages in reinforced concrete (RC) and masonry structures. Since its enforcement, this assessment method has been successfully used after several earthquakes that took place in Turkey, such as 2011 Van Earthquake, 2011 Kutahya Earthquake, 2019 Istanbul Earthquake and 2020 Elazig Earthquake to decide the future of damaged structures to be either ‘repaired’ or ‘demolished’.Scopus - Affiliation ID: 6010507

Structural assessment of the 13th century great mosque and hospital of Divrigi: A world heritage listed structure

. The Great Mosque and Hospital of Divrigi is located in the central eastern part of Turkey, in Divrigi, Sivas. The historical facility consists of a monumental mosque and a two-story hospital, which are adjacent to each other. The structure dates back to 13th century Mengujekids period and has been listed by the UNESCO as a World Heritage since 1985. Great Mosque and Hospital of Divrigi is particularly notable for its monumental stone portals that are decorated with three-dimensional ornaments carved from stone. The structural system of the monument consists of multi-leaf stone masonry walls and stone piers that support the roof structure which consists of stone and brick arches and vaults. The structure is located about 90 km away from the North Anatolian Fault Line, that has been causing several destructive earthquakes. Consequently, the structure is prone to destructive seismic activities. In this study, after a brief introduction on the structural system and current condition of the structure, the structural performance of the Great Mosque and Hospital of Divrigi is investigated through site observations and structural analyses. For this purpose, linear and nonlinear 3D finite element models of the structure are developed and the structure is examined under the effects of vertical loads and seismic actions. In the light of the analyses results, recommendations for potential interventions are outlined for further preservation of the structure

Recurrence in Uterine Tumors with Ovarian Sex-Cord Tumor Resemblance: A Case Report and Systematic Review

Objective: The aim of this study was to evaluate the prognostic factors of recurrence in uterine tumors resembling ovarian sex-cord tumors (UTROSCT) and to determine clinical-pathological characteristics, treatment options and outcome. Material and Method: An electronic literature search was conducted from 1976 to 2018. After the comprehensive evaluation and conjunction with our case, the study included 79 cases. Results: The median age at initial diagnosis was 49 years (range; 16-86 years). The age was under 40 years in 21 (26.6%) patients. Whereas 68 patients underwent at least hysterectomy, 9 patients had organ sparing surgery. There was necrosis in 4 (5.1%) patients, atypia in 16 (20.3%) patients, and infiltrative tumor border in 34 (43%) patients. At least one mitosis per 10 high power fields was determined in 36 (45.5%) patients. The tumor involved at least part of the myometrium in 54 (68.3%) patients. Median follow-up time was 30 months (range; 3-296 months). Recurrence was determined in 5 (6.3%) patients. The disease free survival (DFS) was significantly related only to surgery type. None of the pathologic features were associated with DFS. The 5-year DFS was 86% and 96% in patients who underwent organ sparing surgery or not, respectively (p=0.038). Conclusion: The accurate pathologic diagnosis of UTROSCT has great value in shaping surgical management and management during the follow-up period. Organ sparing surgery was related to poor DFS. Although recurrence is rare, it should be kept in mind for patients with UTROSCT

The Assessment and Reduction of Motion Artifact in Dry Contact Biopotential Electrodes

The connecting interface between biopotential monitoring systems and the human body is the electrode. Conventional medical electrodes use gel to improve skin-electrode contact and glue to provide secure attachment of the electrode to the skin. However, this type of electrode is neither reusable nor user-friendly when implemented in wearable monitoring systems. For wearable monitoring systems, the best type of electrode to use, as seen from the point of view of user comfort and ease of use of the wearable system, is the un-gelled electrode. The un-gelled electrode foregoes conductive gel and attachment glue and instead uses body moisture and clothing pressure to provide contact and secure attachment. The drawback of un-gelled electrodes is that they are susceptible to the wearer’s movements, namely, to motion artifact.Solving the issue of motion artifact will improve signal quality and reliability for wearable systems and, due to integration and reusability, would reduce costs. These two factors, when combined, would enable the widespread use of wearable monitoring systems in both the medical context and the consumer-user context. One effect of this will be a reduction in load and costs on health care systems due to improved preventive monitoring and better monitoring of patients in the recovery and rehabilitation phase. A second effect, combined with the information exchanging channels between individuals, will be unforeseen developments in health science due to what can be called the crowdsourcing of some aspect of physical and mental health and fitness.This thesis aims to further state-of-the art wearable physiological monitoring by aiding motion artifact research and electrode design. To accomplish this aim, investigations into the programmable and repeatable generation of electrode movement in order to generate motion artifact, the effect of impedance current frequency on the relationship between skin-electrode interface impedance and electrode movement and motion artifact, the effect of using an electrode support structure and how its design affects the motion artifact, and the effects of garment parameters such as tightness are presented in this thesis.A system that generates known and programmable motion of the electrode under controlled circumstances was designed, tested, and after the verification of system functionality, used in subsequent investigations. The presented system generates accurate motion of the electrode and the electrode motion can be observed as both motion artifact and skin-electrode impedance changes.A real time impedance spectroscopy study of 24 impedance current frequencies between 25 Hz and 1 MHz was done on electrodes subject to accurately known motion generated by the designed system in order to find the impedance current frequencies most suited to motion artifact studies.During this research, a hypothesis was formed that states that an electrode with a structural design that restricts epidermis deformation by trapping the epidermis under the electrode area can reduce motion artifact. Different electrode support structures were designed in order to test this hypothesis. The electrodes with support structures were subjected to system-generated motion and the resulting data were analyzed for the verification of support structure functionality and the hypothesis.Electrodes that were supported by a tight garment-mimicking elastic straps were studied under subjectgenerated movement and at various clothing tightness levels. The same study was used to understand the effect of using padding between the garment and the electrode.The motion artifact generation system was seen to be successful in accurately generating electrode motion, thus motion artifact, which was programmable and repeatable. The electrode mounting force monitoring proved to be an important functionality as the mounting force was seen to affect the motion artifact.Skin-electrode impedance was found to correlate well with electrode motion in current frequencies between 17 kHz and 1 MHz. While the correlation between impedance and motion artifact was lower than the correlation between impedance and electrode motion, it was also highest in this frequency band.Electrode support structure design is seen to be an important factor to consider when designing the electrode, and the electrodes that came closest to fulfilling the design criteria of the hypothesis were the best functioning electrodes. The hypothesis is seen to be promising and electrodes that distributed skin deformation over a large area and/or restrict epidermis deformation were found to reduce motion artifact.In the presented studies, the pressures under those electrodes that were found to be the most effective in reducing motion artifact differed between experiments yet stayed in a range between 5 mmHg -36 mmHg (0.66 kPa – 4.80 kPa). A simple guideline is that the electrode should be attached firmly but not so firmly that it becomes uncomfortable. This guideline fitted well with the pressure levels found for each experiment.The presented Motion Artifact Generation and Assessment System can be used for research or commercial purposes, furthering the research on motion artifact and aiding in the successful design of motion artifact resilient electrodes. The issue of which are the best current frequencies to use to measure skin-electrode interface impedance in motion artifact research has been clarified. Possible means of reducing motion artifact at its origin by using structural electrode designs that restrict epidermis deformation is hypothesized and proven worthy of further research. The importance of garment design and guidelines for use are given and tightness recommendations presented. The thesis presents methodology for the furthering of the understanding of motion artifact and electrode design that will eventually make wearable monitoring systems widespread over a large range of applications and a large number of users

Gayrimenkul yatırım ortaklıklarında finansal yapı, büyüme, strateji ve portföy teorisi prensiplerinin gayrimenkul portföyüne uygulanması

ÖZETGayrimenkul Yatırım Ortaklıkları (GYO), Türkiye'deki sermaye piyasalarında kısa bir geçmişe sahip olduğu ve bu geçmişinde ağır ekonomik krizlerle tanıştığı için, gerek kurucuları ve yöneticileri ve gerekse yatırımcılar tarafından ümit edilen performans, likidite ve güvenilirlik farklarını ortaya koyamamışlardır.GYO'lar sermaye piyasalarının değişkenliğinden, en az halka açık diğer kuruluşlar kadar etkilenmektedirler (GYO hissesi almış olmak, diğer hisse senetlerine sahip olmaktan farklı değil, diğer bir deyişle GYO hissesi gayrimenkul değil). GYO'lar genelde büyük grupların ellerindeki gayrimenkulleri sattıkları ve geri kiraladıkları kuruluşlar olagelmişlerdir. Bu eğilime, ekonomideki durgunlukta proje geliştirmenin verimsizliği de eklendiğinde, büyüme politikaları, yatırımları ve gelir kompozisyonları belirlenmiş, reel olarak analiz edilebilir GYO'lardan oluşan bir GYO sektörü oluşmasının zaman alacağı görülmektedir.GYO'ların gayrimenkul ve inşaat sektörüne kalite ve ekonomik canlılık getirmesi beklenmektedir. GYO'lar, gayrimenkul talebi ve kullanımındaki değişikliklere uyum sağlama ve hatta yeni eğilimler yaratma potansiyeline sahiptir. GYO'lar, gayrimenkul yatırımcılığının gelecekteki şeklini belirlemelidir.Yatırım portföylerindeki yeri itibarıyla GYO'lar, gayrimenkulun ve getirisinin verdiği güveni, hisselerine tam olarak yansıtabildiklerinde, daha sağlam ve uzun vadeli yatırım aracı olabileceklerdir. GYO'nun yatırım aracı olarak öne çıkması, finansal yapısına, portföy yapısına, portföyünün getiri-risk dengesine ve değer yaratıp yaratamadığına bağlıdır. Bu çalışmanın amacı; GYO'nun finansal yapısındaki temel başlıkları ele alarak gelir yaratma mekanizmalarını ve büyümenin nasıl sağlandığını aktarmak; günümüzde GYO'ların sorunlarını ele alıp bazıları için çözüm önerilerinde bulunmak, portföy oluşturma ve yönetim stratejilerine değinmek, GYO'ların gayrimenkul portföyünün oluşturulması ve yönetiminde, Modern Portföy Teorisi'nin temel prensiplerinden yararlanılabileceği konusunda örnekler verip önerilerde bulunmaktır. Bu kapsamda gelişmiş ekonomilerdeki GYO'larla ilgili bilgiler verilmiş ve karşılaştırma imkanı sağlanmaya çalışılmıştır.Birinci bölümde çalışmanın kapsamı, amacı ve yöntemi aktarılmıştır. İkinci bölümde kısaca GYO'nun tanımı, fonksiyonu ve yapısı anlatılmış, büyümenin dinamiklerinden bahsedilirken, GYO'nun gelir yaratma şekilleri açıklanmış ve bu gelirlerin, büyümeyi sağlamaya yönelik değerlendirilme yöntemleri ele alınmıştır. Bölümün son kısmında ise GYO'ların karşı karşıya olduğu riskler sınıflanmış ve kısaca açıklanmıştır. Üçüncü bölümde GYO'nun finansal analizi yapılarak, GYO yatırımcısının yapması gereken hesaplamalara ve sorması gereken sorulara değinilmiştir.Dördüncü bölümde, GYO'nun iki temel yatırım faaliyetine, gayrimenkul geliştirme (development) ve gayrimenkul edinme (acquisition) süreçlerine ayrıntısıyla değinilmiş ve GYO yatırımlarının "değer" yaratması için gerekli önemli noktalar vurgulanmıştır. ABD ve Avrupa'da GYO'nun gayrimenkul portföyünü oluşturmasında uygulanan portföy oluşturma ve çeşitlendirme stratejilerinden bahsedilmiş ve Modern Portföy Teorisi, gerekli detayda kısaca aktarılmıştır.Modern Portföy Teorisi'nin temel prensiplerinin, gayrimenkul portföyünün oluşturulmasında ve risk-getiri niteliklerinin takibindeki kullanılabilirliği ele alınarak, örnek çözümler yapılmış ve dikkat edilmesi gereken noktalar vurgulanmıştır. Gayrimenkul projelerinin risk analizi konusu, bu çalışmanın kapsamı dışındadır. Çözümlerde, örnek hayali gayrimenkul projelerinin, olasılık ve duyarlılık analizi sonuçları kullanılmıştır. Sonuçlar yorumlanmış ve gerçek hayattaki uygulanabilirliğine değinilmiştir. Bu konudaki öneriler, diğer olumlu etkileri ile birlikte, Sonuç ve Öneriler kısmında yer almıştır. Ayrıca, hesaplama yönteminin daha etkin uygulanabilmesi için gereken verilerden bahsedilmiş ve Türkiye'ye özgü veri eksikliklerine dikkat çekilmiştir. Eksik verilerin oluşturulmasına yönelik kaynak ve hesaplama yöntemi önerisi, Sonuç ve Öneriler kısmında yeralmıştır.Beşinci bölümde, yatırım portföyleri içinde GYO'nun ve gayrimenkulun yeri ve etkisi, gelişmiş ekonomilerle karşılaştırma yapılarak işlenmiştir. Günümüzde GYO'ların sorunlarına değinilmiş ve bu kapsamdaki öneriler, Sonuç ve Öneriler kısmında belirtilmiştir. Ayrıca bu bölümde GYO'ların geleceği ile ilgili görüşler değişik yönleriyle aktarılmış ve GYO'ların etkileri incelenmiştir.Sonuç ve Öneriler bölümünde, çalışma kapsamında ele alınan konulara paralel olarak GYO sektörü; yönetim, yatırım, faaliyet şekilleri gibi değişik açılardan değerlendirilmiştir. Değer yaratma ve yatırımcıya kazandırma perspektifinde eleştiriler yapılmış, olması ve olmaması gerekenler vurgulanmıştır. GYO sektörünün sorunlarına, gayrimenkule "portföy" bakış açısı getirilmesi gereğine ve analitik yöntemlerin önemine dikkat çekilmiştir. Portföy teorisinin temel prensiplerinin gayrimenkul yatırım portföylerinin oluşturulması ve izlenmesindeki kullanım alanları ve yöntemleri, bu çerçevede Türkiye'deki eksiklikler ve öneriler bu bölümde aktarılmıştır. Önerilerin aktarımında objektif olunmaya çalışılmış, sadece ele alındığı başlık kapsamında değil, sektörel etkileri ile vurgulanmaya çalışılmıştır.Ek A, B, ve C'de, GYO ve gayrimenkul sektörü ile ilgili güncel ve ilgi çekici bilgiler derlenmiştir.SUMMARYREAL ESTATE INVESTMENT TRUSTS' FINANCIAL STRUCTURE, GROWTH, STRATEGY AND THE APPLICATION OF BASIC PRINCIPLES OF PORTFOLIO THEORY TO PROPERTY PORTFOLIOReal Estate Investment Trusts (REIT) have a short history in Turkiye's capital markets. Due to heavy economic circumstances -which can be also called as a crisis at this stage- in their short history, they were not able to provide the anticipated performance, liquidity and reliability as an investment vehicle.REITs are sharply influenced by the volatility of capital markets as other securities are. REITs also became partnerships of holdings who sell their real estates to REIT and lease them back. In addition to founder group operations, the non-profitability of project development activities in economic slow-down results in a postponement of an analyzable REIT sector formation in growth policies, investments and revenue compositions.REITs have the high potential to adapt emerging new trends in real estate demand and usage. REITs will determine the future formation of investing in real estate.The high preference of REITs as an investment alternative depends on its value creating capability, financial structure and return-risk expectations of the portfolio.The goals of this thesis are;-to describe the growth and income generating mechanisms of REITs,-to touch on the current problems of REITs,-to explain portfolio structuring and managing strategies,-to examine the basic principles of portfolio theory in property portfolio structuring and managing.In the first chapter -that is the introduction- subject, objective and methodology of the study are explained. In the second chapter, REIT's definition, function and structure are given shortly and the growth dynamics of revenues of REIT's are explained.In the third chapter, the financial analysis of REIT has been made. In the fourth chapter, two main investment activities; acquisition and development have been touched on in detail and followed with the explanation of property portfolio structuring strategies in the USA and Europe.The Portfolio Theory's basic principles are summarized and thus the application of these principles to property portfolio structuring, managing and return-risk evaluation is focused through imaginary examples and calculations. The outcomes of these examples are interpreted and the real-life applications are put forth.In the fifth chapter, the real estate's and REIT's function and effect in mutual funds are vividly illustrated. Also current problems of REIT's in Turkiye are mentioned along their estimated future role functions.In the final chapter, the REIT sector is evaluated in terms of management and investment strategy. The importance of the analytical methods while making the investment decision is emphasized and the "portfolio point of view" to real estates and projects is highlighted. Consequently, the suggestions for using the basic principles of portfolio theory are shown along warning signs.In Appendices, the current and striking information about REITs and real estate sector is shared

ERKEN BAŞLANGIÇLI PROGRESİF TUTUK AFAZİ

Progressive nonfluent aphasia is a slowly progressive degenerative disease characterized by atrophy in left hemisphere particularly frontotemporal. It is one of three subtypes of frontotemporal lobar degeneration (frontotemporal dementia). Unlike Alzheimer’s disease it begins between 45-65 years of age and occurs equally in both sexes usually. The reported youngest case was 21 years old. Atrophy is seen in the left hemisphere more in temporal lobe on magnetic resonance imaging. Approximately half of the cases have family history. In early it might confuse with depression and therefore diagnosis may be delayed. Brain magnetic resonance imaging is important for verification of diagnosis. In this paper, a case who early onset progressive nonfluent aphasia was mentioned