On the passivity of interaction control with series elastic actuation

Regulating the mechanical interaction between robot and environment is a fundamentally important problem in robotics. Many applications such as manipulation and assembly tasks necessitate interaction control. Applications in which the robots are expected to collaborate and share the workspace with humans also require interaction control. Therefore, interaction controllers are quintessential to physical human-robot interaction (pHRI) applications. Passivity paradigm provides powerful design tools to ensure the safety of interaction. It relies on the idea that passive systems do not generate energy that can potentially destabilize the system. Thus, coupled stability is guaranteed if the controller and the environment are passive. Fortunately, passive environments constitute an extensive and useful set, including all combinations of linear or nonlinear masses, springs, and dampers. Moreover, a human operator may also be treated as a passive network element. Passivity paradigm is appealing for pHRI applications as it ensures stability robustness and provides ease-of-control design. However, passivity is a conservative framework which imposes stringent limits on control gains that deteriorate the performance. Therefore, it is of paramount importance to obtain the most relaxed passivity bounds for the control design problem. Series Elastic Actuation (SEA) has become prevalent in pHRI applications as it provides considerable advantages over traditional sti actuators in terms of stability robustness and delity of force control, thanks to deliberately introduced compliance between the actuator and the load. Several impedance control architectures have been proposed for SEA. Among the alternatives, the cascaded controller with an inner-most velocity loop, an intermediate torque loop and an outer-most impedance loop is particularly favoured for its simplicity, robustness, and performance. In this thesis, we derive the necessary and su cient conditions to ensure the passivity of the cascade-controller architecture for rendering two classical linear impedance models of null impedance and pure spring. Based on the newly established passivity conditions, we provide non-conservative design guidelines to haptically display free-space and virtual spring while ensuring coupled stability, thus the safety of interaction. We demonstrate the validity of these conditions through simulation studies as well as physical experiments. We demonstrate the importance of including physical damping in the actuator model during derivation of passivity conditions, when integral controllers are utilized. We note the unintuitive adversary e ect of actuator damping on system passivity. More precisely, we establish that the damping term imposes an extra bound on controller gains to preserve passivity. We further study an extension to the cascaded SEA control architecture and discover that series elastic damping actuation (SEDA) can passively render impedances that are out of the range of SEA. In particular, we demonstrate that SEDA can passively render Voigt model and impedances higher than the physical spring-damper pair in SEDA. The mathematical analyses of SEDA are veri ed through simulations

Evaluation of genotype x environment interactions in maize hybrids using GGE biplot analysis

Seventeen hybrid maize genotypes were evaluated at four different locations in 2005 and 2006 cropping seasonsunder irrigated conditions in Turkey. The analysis of variance showed that mean squares of environments (E), genotypes (G) andGE interactions (GEI) were highly significant and accounted for 74, 7 and 19 % of treatment combination sum squares, respectively.To determine the effects of GEI on grain yield, the data were subjected to the GGE biplot analysis. Maize hybrid G16 can be proposedas reliably growing in test locations for high grain yield. Also, only the Yenisehir location could be best representative of overalllocations for deciding about which experimental hybrids can be recommended for grain yield in this study. Consequently, using ofgrain yield per plant instead of grain yield per plot in hybrid maize breeding programs could be preferred by private companies dueto some advantages

Benzetilmiş Tavlama Algoritması İle Fazör Ölçüm Birimlerinin Optimal Yerleşimi

Gelişen teknoloji ve artan nüfus ile birlikte elektrik enerjisine olan ihtiyaç ve talep her geçen gün artmaktadır. Enerji talebindeki artış güç sistemlerini kararlılık sınırlarına yakın bölgelerde çalışmaya zorlamaktadır. Bu durum güç sistemlerinde gerilim kararsızlığı ve gerilim çökmesi gibi sonuçlar doğurmaktadır. Güç sistemlerinin kararlılık durumunun gerçek zamanlı olarak takip edilmesi kritik önem taşımaktadır. Bu sebeple güç sistemlerinin izlenebilirliği ve kontrolünü sağlayan sistemlere duyulan ihtiyaç da artmıştır. Fazör Ölçüm Birimi (FÖB) bu sistemlerden birisidir. FÖB’ler Global Positioning System (GPS) yardımıyla gerilim, akım ve faz açısının anlık olarak takip edilmesine imkan sağlamaktadır. Ancak maliyet kısıtı nedeniyle FÖB’ler iletim hatlarında tüm baralara yerleştirilememektedirler. Bu yüzden FÖB’leri şebekeye maksimum gözlenebilirliği sağlayacak optimal bir şekilde yerleştirmek önem arz etmektedir. Optimal yerleşim için literatürde pek çok yöntem kullanılmaktadır. Bu çalışmada Benzetilmiş Tavlama Algoritması kullanılarak Enterkonnekte güç sisteminin bir kısmı olan Trakya Güç Sistemi’ne optimal FÖB yerleşimi yapılmıştır. Benzetilmiş Tavlama Algoritması ile elde edilen sonuçlar, Power System Analysis Toolbox (PSAT) programı ile FÖB yerleşim algoritmalarından çıkan sonuçlarla karşılaştırılmıştır. Bu çalışma ile sistemin tamamını anlık olarak takip edebilmek için kullanılan FÖB’lerinin, Trakya Güç Sistemi’nde hangi baralara yerleştirilmesi gerektiği tespit edilmiş ve optimal yerleşim gerçekleştirilmiştir

Books Received

WOS: 000324163700028In this study, estimation of narrow sense heritability, genetic correlations and relative effects of direct versus indirect selection were aimed for peduncle length, spike length, number of spikelet per spike and number of kernels per spike as selection was applied for shorter plant height in common wheat population of (Golia x Atilla-12) cross. While the indirect effect of direct selection for plant height was observed negative on number of kernels per spike, positive effect was obtained on peduncle length. It was understood that selection of peduncle length can be done indirectly through the selection for short plant height in the (Golia x Atilla-12), but while it had no effect on other components. Therefore, it was concluded that direct selection for short plant height can be done successfully, and on various selection practices and studies are necessary for the spike length, number of spikelet per spike and number of kernels per spike. (C) 2013 Friends Science Publisher

Recurrence rate of odontogenic keratocyst treated by enucleation and peripheral ostectomy : retrospective case series with up to 12 years of follow-up

Odontogenic keratocysts have been reported with high recurrence rates in the literature so various treatment modalities from simple enucleation to resection have been performed to achieve the cure. The purpose of this retrospective study was to investigate the recurrence rate of odontogenic keratocysts (OKCs) treated by enucleation and peripheral ostectomy. An electronic search of the database of the Hacettepe University, Faculty of Medicine, Department of Pathology, was undertaken to identify patients histologically diagnosed with OKCs treated at Department of Oral and Maxillofacial Surgery between 2001 and 2015. In total, 81 patients were studied. The mean age at the time of diagnosis was 42 years, and the male:female ratio was 1:0.7. OKCs were located primarily in the posterior mandibular region (41%). Twenty-seven patients were re-examined to determine the recurrence rate. The mean follow-up period was 5 years (range, 1?12 years). The recurrence rate was 14.8%. The relationship between location of the lesion and recurrence was not statistically significant (p = 0.559). There was also no statistically significant relation between the recurrence rate and treatment option of teeth involved in the lesion (p = 0.579). The authors conclude that treatment of OKCs by enucleation with peripheral ostectomy is associated with minimal morbidity and is preferred over other aggressive treatment modalities. Meticulous radiographic examination and careful surgical resection may decrease the recurrence rate of OKCs

Development and management of ovarian hyperstimulation syndrome in spontaneous singleton pregnancy

Ovarian hyperstimulation syndrome (OHSS) is one of the most life-threatening complications of ovulation induction. However, rarely, OHSS can develop spontaneously during pregnancy without induction of ovulation. It has been shown in the literature that some diseases such as polycystic ovary syndrome (PCOS), hypothyroidism, and pituitary adenoma may accompany spontaneous OHSS. Spontaneous OHSS should be included in the differential diagnosis in first-trimester pregnancies with nausea, vomiting, and acute abdomen. The focus should be on preventing possible complications and initiating early treatment immediately after diagnosis

Identification of resistance to Eurygaster integriceps Put. on some bread wheat genotypes

Sunn pest (Eurygaster integriceps Put.) is one of the most important pests of wheat in Eastern Europe including Turkey, West and Cen-tral Asia. Its damage on leaves, stems, spikes and grains reduce the baking quality of flour made from damaged grains. In this study, some wheat genotypes from Turkey and ICARDA were evaluated for the pest resistance. The genotypes were planted in a randomized block design using hill plots in nylon mesh screening cages in wheat growing season of 2011-2012 and 2012-2013. Sunn pest population was collected from Çanakkale province, where the pest was intensely found in recent years. The plants of each hill plots were infested with one male and one female Sunn pest adults. The results with 12.5% sucking damage showed that the genotypes from ICARDA had higher resistance than the landraces from Turkey to Sunn pest. Especially, the genotypes IC3 and IC4 from ICARDA and TR7 from Turkey with respect to their SED and DSED values were found the most promising genotypes resistant to Sunn pest for future breeding programs

Skin manifestations following anti-COVID-19 vaccination: A multicentricstudy from Turkey

Purpose: After the emergence of the pandemic caused by the COVID-19 virus, vaccination with various vaccines has started to be implemented across the world. To identify dermatological reactions developing after the COVID-19 vaccines administered in Turkey and determine their clinical features and risk factors that may play a role in their development. Materials and Methods: The study included patients aged ≥18 years, who presented to 13 different dermatology clinics in Turkey between July 2021 and September 2021 after developing dermatological reactions following the administration of the COVID-19 vaccine. After providing written consent, the patients were asked to complete a standard survey including questions related to age, gender, occupation, comorbidities, the regular medication used, the onset of cutaneous reactions after vaccination, and localization of reactions. Dermatological reactions were categorized according to whether they developed after the first or second dose of the vaccine or whether they occurred after the inactivated or messenger RNA (mRNA) vaccine. The relationship between dermatological reactions and some variables such as gender and comorbidities was also evaluated. Results: A total of 269 patients [116 women (43.1%), 153 men (56.9%)] were included in the study. It was observed that the dermatological diseases and reactions that most frequently developed after vaccination were urticaria (25.7%), herpes zoster (24.9%), maculopapular eruption (12.3%), and pityriasis rosea (4.5%). The rate of dermatological reactions was 60.6% after the administration of the mRNA vaccine and 39.4% after that of the inactivated vaccine. There was a statistically significantly higher number of reactions among the patients that received the mRNA vaccine (p = 0.001). Conclusion: The most common reactions in our sample were urticaria, herpes zoster, and maculopapular eruption. Physicians should know the dermatological side effects of COVID-19 vaccines and their clinical features

Naiv hepatit C enfeksiyonlu hastaların on-altı yıllık prognozu

Objectives: In this study, we aimed to evaluate the clinical course of treatment-naive patients infected with hepatitis C virus (HCV) who were followed up in various centers in Turkey. Materials and Methods: This was a retrospective study performed with the participation of 15 centers. Patients aged 18 years and older with HCV infection were included. Results: A total of 391 treatment-naive patients infected with HCV were included in this study. During the follow-up period, the final values of alanine aminotransferase, aspartate transaminase, and total protein were significantly decreased when compared to the initial values (p<0.001, p<0.001, and p=0.005, respectively). In the study group, 19.2% of the patients underwent liver biopsy and 4.1% underwent transient elastography (FibroScan). An increased histological activity index (HAI) score and fibrosis in the second biopsy were observed in one patient, only increased HAI in two patients and increased fibrosis in one patient, as shown on the FibroScan. In the 16 years of the study period, cirrhosis was radiologically detected in only one patient. Conclusion: Even if rapid progression is not observed, close monitoring of the clinical findings related to liver failure and fibrosis with invasive or non-invasive methods may be useful.Amaç: Bu çalışmada ülkemizin çeşitli merkezlerinde takip edilen naiv hepatit C virüs (HCV) ile enfekte hastaların klinik seyrini değerlendirmeyi amaçladık. Gereç ve Yöntemler: Bu çalışma retrospektif olarak 15 merkezin katılımıyla gerçekleştirilmiştir. Çalışmaya 18 yaş üstü, HCV enfeksiyonu olan hastalar dahil edilmiştir. Bulgular: Çalışmada 391 tedavi-naiv HCV enfeksiyonlu hasta yer almıştır. Hastaların takip süresinde son alanine aminotransferase, aspartate transaminase ve total protein değerleri ilk düzeyine göre önemli düzeyde azalmıştır (sırasıyla p<0,001, p<0,001, p=0,005). Çalışma grubunda hastaların %19,2’sine karaciğer biyopsisi, %4,1’ine elastografi (FibroScan) uygulanmıştır. Takip esnasında bir hastada ikinci biyopside histolojik aktivite indeksi (HAI) ve fibroziste artma, iki hastada sadece HAI’da artma, birinde FibroScan ile fibrozis değerinde artma olduğu gözlenmiştir. Bir hastada 16 yıl içinde radyolojik olarak siroz saptanmıştır. Sonuç: Hızlı progresyon gözlenmemekle birlikte hastaların izleminde karaciğer yetmezliği ile ilgili klinik bulguların ve invaziv veya noninvaziv yöntemlerle fibrozisin yakın takibi yararlı olabilir