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Combinational of surrogate modeling and particle swarm optimization for improving the electromagnetic performances of a frequency selective surface
No full textFrequency-selective surfaces (FSSs) consist of the repetition of unit cells for controlling reflection, transmission/absorption of electromagnetic (EM) fields. They are typically employed at radio and optical frequencies. Simulation of such large (in terms of wavelength) structures based on the traditional EM simulations is time-consuming and requires significant computational resources. Hence, this paper devotes to present an optimization-oriented methodology for designing and optimizing FSS in an automated fashion. The FSS structure is optimized using the artificial neural network paradigm, where the particle swarm optimization is applied for sizing the design parameters. The optimization process is an automatic one where electronic design automation tool with numerical analyser is working together, leading to effectively optimize the FSS design. To verify the effectiveness of the proposed method, an FSS structure exhibiting a wide transmission band for normal incidence in the 7.0-11.2 GHz range is considered
İHRACAT İŞLEMLERİNDEN ELDE EDİLEN DÖVİZ GELİRİNİN ZORUNLU SATIŞI VE REESKONT KREDİSİ KULLANIMININ MUHASEBELEŞTİRİLMESİ
No full textÜlke ekonomilerinde katma değer yaratan ihracat döviz gelirleri ödemeler dengesinin sağlanmasının da önemli bir aracıdır. Dünyayı etkileyen ekonomik kriz karşısında Türkiye özellikle dış ticaret açığının, enerji dar boğazının ve cari açığın getirdiği sorunları giderebilmek için birtakım önlemler almıştır. Bu önlemlerden bir tanesi de Türkiye’ ye getirilecek ihracat geliri döviz miktarının belirli bir oranda Türkiye Cumhuriyet Merkez Bankasına (TCMB) satış zorunluluğudur. Zorunlu satışın dışında kalan döviz gelirinin belirlenen bir oran dahilinde diğer bir bankaya satılması ve bu satışların karşılığında ihracat reeskont kredisi kullandırılması da alınan önlemin bir parçasıdır. Çalışmanın amacı; işletmelerin ihracat işlemlerinden elde ettikleri döviz gelirlerinin belli bir oran dâhilinde zorunlu olarak TCMB’ye, isteğe bağlı olarak da bir başka bankaya satışı ve bu döviz satışları karşılığında İhracat ve Döviz Kazandırıcı Hizmetler Reeskont Kredisi kullandırılmasının yevmiye kayıtlarının gerçekleştirilmesidir. Çalışmanın yöntemi, örnek muhasebe uygulamasıdır. TCMB’nin döviz rezervlerine olumlu katkı sağlayan uygulama birtakım sorunları da beraberinde getirmektedir. Çalışmanın sonucunda; işletmeler açısından, zorunlu ve isteğe bağlı döviz satışlarının düşük kurdan yapılmasının finansal kayıplara yol açtığı, ihracat reeskont kredisinin kullanılması için satılması gereken döviz miktarını belirleyen oranın yüksek olduğu, ihtiyaç duyulan dövizin tekrar alınması halinde ilave maliyete katlanılacağı, uygulamayı içeren muhasebe kayıtlarının mevzuata uygun bir şekilde tutulmasının işlemleri kolaylaştıracağı tespit edilmiştir
Relationship between platelet indices and red cell distribution width and short-term mortality in traumatic brain injury with 30-day mortality
No full textOBJECTIVE: This study aimed at investigating whether there is a relationship between 7- or 30-day mortality and mean platelet volume, platelet distribution width, platelet count-to-total lymphocyte count ratio, or red cell distribution width in patients with traumatic brain injury.METHODS: We retrospectively analyzed intensive care unit patients with traumatic brain injury. We recorded patients' ages; genders; diagnoses; Glasgow Coma Scale scores; length of intensive care unit stay (in days); mean platelet volume, platelet distribution width, platelet count-to-total lymphocyte count ratio, and red cell distribution width values upon hospital admission; and health on the 7th and 30th days of their stays.RESULTS: We analyzed data from 110 patients. Of these, 84 (76.4%) were male and 26 (23.6%) were female. On the 7- and 30-day mortality evaluations, compared to the living patients, the deceased patients had a significantly higher median age and a significantly lower median Glasgow Coma Scale. Thus, increased age and lower Glasgow Coma Scale scores were associated with increased 7- and 30-day mortality rates. mean platelet volume and platelet distribution width values were similar in living and deceased patients. platelet count-to-total lymphocyte count ratio values were lower in deceased patients, but this difference was not statistically significant. Within 30 days after traumatic brain injury, deceased patients' red cell distribution width values were significantly elevated in deceased patients compared to those of living patients. CONCLUSION: Mean platelet volume, platelet distribution width, and platelet count-to-total lymphocyte count ratio values were not associated with 7- and 30-day mortality, whereas only elevated red cell distribution width was associated with 30-day mortality
Generation of the form cutter profile from the groove profile for one-pass external helical milling: An inverse problem
No full textOne-pass is a term used to shape parts without the need for consecutive cuts in machining. Therefore, it is a method to enable cost-effective machining. However, generating the tool geometry and path for a given volume by one-pass milling may rarely be possible. Although the generation of the machined part surface in machining has been widely discussed in the literature, the investigation of such inverse problems is very few. In this paper, helical external grooves were considered. It was demonstrated that it is possible to perform one-pass milling for helical grooves in most cases using a dedicated form cutter. The profile of the form cutter based on the groove profile was derived by an iterative approach using Python programming language. It was considered that the form cutter is the composition of the circles, and the trace of each circle must be in contact with the groove profile in a reference plane. The diameter of each circle was derived using this contact condition. Then, the circles were combined to create the form cutter. Several groove profiles were investigated, and the profiles of the form cutters were obtained. Experimental verification was presented for one of the examples
Input Shape Effect on Classification Performance of Raw EEG Motor Imagery Signals with Convolutional Neural Networks for Use in Brain-Computer Interfaces
No full textEEG signals are interpreted, analyzed and classified by many researchers for use in brain-computer interfaces. Although there are many different EEG signal acquisition methods, one of the most interesting is motor imagery signals. Many different signal processing methods, machine learning and deep learning models have been developed for the classification of motor imagery signals. Among these, Convolutional Neural Network models generally achieve better results than other models. Because the size and shape of the data is important for training Convolutional Neural Network models and discovering the right relationships, researchers have designed and experimented with many different input shape structures. However, no study has been found in the literature evaluating the effect of different input shapes on model performance and accuracy. In this study, the effects of different input shapes on model performance and accuracy in the classification of EEG motor imagery signals were investigated, which had not been specifically studied before. In addition, signal preprocessing methods, which take a long time before classification, were not used; rather, two CNN models were developed for training and classification using raw data. Two different datasets, BCI Competition IV 2A and 2B, were used in classification processes. For different input shapes, 53.03-89.29% classification accuracy and 2-23 s epoch time were obtained for 2A dataset, 64.84-84.94% classification accuracy and 4-10 s epoch time were obtained for 2B dataset. This study showed that the input shape has a significant effect on the classification performance, and when the correct input shape is selected and the correct CNN architecture is developed, feature extraction and classification can be done well by the CNN architecture without any signal preprocessing
Nasal obstruction in adults: how it affects psychological status?
No full textObjectiveThis study investigated the psychological status of patients with unilateral or bilateral complete nasal obstruction.MethodThe study included 49 consecutive cases of unilateral or bilateral complete nasal obstruction. In order to assess participants' personality traits, both groups completed the Personality Belief Questionnaire, State-Trait Anxiety Inventory form, Beck Depression Inventory and Beck Anxiety Inventory.ResultsThe groups were similar in terms of demographic characteristics. Patients with unilateral or bilateral complete nasal obstruction had higher scores on all the psychological assessments compared with the healthy controls, except for the Beck Anxiety Inventory. Although all personality assessment scores were higher in patients, the only differences that were statistically significant were in the dependent, antisocial and avoidant personality trait scores.ConclusionThe psychological conditions of patients with structural deformities that cause nasal obstruction may be affected, and appropriate treatment should be provided to improve their symptoms and quality of life
An efficient analytical model for the swept volume generation of a flat-end mill in 5-axis CNC milling
No full text5-axis CNC (Computer Numerical Control) milling is widely used to create complex part geometries in the industrial area. The cutting tool creates the swept volume as it moves along the defined path. The swept volume is subtracted from the initial stock for the machining simulation. Although a swept volume consists of three parts such as ingress, egress, and swept envelope, the number of faces of the swept volume is higher than three. In this work, parametric equations of the faces of the swept volume were obtained for a flat-end mill in four steps. The model is based on the decomposition of the tool into circles along the tool orientation vector since a flat-end mill can be modeled as a cylinder. The fundamental principle is that each circle is tangent to the swept envelope of the cylinder. Locations of the grazing points with respect to a local coordinate system were determined by applying the Envelope Theory to the parameterized circle of the cylinder. Then, each face of the swept volume was represented based on the equation of the parameterized circle. The model was verified by using an alternative analytical model. As a result, boundaries of the swept volume were represented fully analytically for a flat end mill in 5-axis CNC milling in an efficient way. (c) 2023 Elsevier B.V. All rights reserved
The mediating role of ethical climate on the impact of existentialism on value based leadership
No full textLisansüstü Eğitim Enstitüsü, İşletme Ana Bilim DalıLiderlik, işletmelerde, tüm organizasyonlarda ve genel olarak toplumda çok önemli bir rol oynar. Örgütsel Performans, İnovasyon ve Değişim, Çalışan Gelişimi ve Bağlılığı, Etik Karar Verme, Stratejik Yönetim ve Vizyon, Paydaş İlişkileri gibi alanlarda liderliğin önemi her geçen gün artmaktadır. Baş döndürücü bir hızla değişimin yaşandığı içinde bulunduğumuz dijital çağda yarına bu değişimi sadece yöneten değil, aynı zamanda bu değişimi yaratan bireyler, devletler ve şirketler kalacaktır. Bu bağlamda insanın kendi varoluşunu anlamlandırması, birey olarak değerler sistemine ve etik değerlere sahip olmasının da önemi her geçen gün artmaktadır. Bireylerin ve kurumların var olmaları, varlıklarını sürdürmeleri mücadelelerini başarmalarının yolu, birey olarak, toplum olarak ve şirket olarak gerçek anlamda var olmaktan, varoluşçu ve özgünlüğün potansiyelinin açığa çıkardığı yaratıcı, yenilikçi değer yaratma süreçlerine stratejik lider olarak başarı göstermekten geçmektedir. Bu çalışmada Varoluşçuluğun Değer Merkezli Liderliğe Etkisinde Etik İklimin Aracı Rolü incelenmiş olup, araştırmada İstanbul merkezli halka açık şirketlerde çalışan 420 yönetici ile anket çalışması neticesinde elde edilen verilerle Yapısal Eşitlik Modellemesi ile hipotez testleri test edilmiştir. Araştırma sonuçlarına göre, Varoluşçuluğun Değer Merkezli Liderliğe Etkisinde Etik İklimin Kısmi Aracı Etkisinin olduğu bulunmuştur. Bununla birlikte diğer hipotez test sonuçlarında da teorik olarak anlamlı sonuçlara ulaşılmıştır.Leadership plays a crucial role in businesses, all organizations, and society in general. The importance of leadership is increasing day by day in areas such as Organizational Performance, Innovation and Change, Employee Development and Engagement, Ethical Decision Making, Strategic Management and Vision, Stakeholder Relations. In today's digital age, where change is experienced at a dizzying pace, tomorrow will be individuals, states and companies that not only manage this change, but also create this change. In this context, the importance of making sense of one's own existence, having a system of values and ethical values as an individual is increasing day by day. The way for individuals and institutions to survive, to survive and to succeed in their struggle is to exist as an individual, as a society and as a company, and to be successful as a strategic leader in creative and innovative value creation processes that reveal the potential of existentialism and originality. In this study, the Mediator Role of Ethical Climate in the Effect of Existentialism on Value-Based Leadership was examined, and hypothesis tests were tested with Structural Equation Modelling with the data obtained as a result of the survey with 420 managers working in publicly traded companies founded in Istanbul. According to the results of the research, it was found that the Ethical Climate has a Partial Mediating Effect on the Effect of Existentialism on Value-Based Leadership. In addition to this, theoretically significant results were obtained in other hypothesis test results
MIMO Antenna Design Through Genetic Algorithm
No full text16th International Conference on Interdisciplinarity in Engineering, INTER-ENG 2022 -- 6 October 2022 through 7 October 2022 -- -- 287969Massive multiple-input multi-output (MIMO) is a technology established more than a decade ago; since then it has been employed as an integral part of the fifth generation (5G) mobile technologies. Recently, MIMO antenna designs have taken the attention of researchers due to their benefits such as reduced bit errors, high throughput, low latency and others. MIMO antennas consist of multiple radiating elements leading to have complex designs. Hence, frequently, optimization-based methods are required during their design; this paper provides one possible optimization-based methodology for designing them. The design procedure starts with configuring the MIMO antenna and then employing the genetic algorithm (GA) for optimizing the design parameters describing the MIMO antenna geometry. Using the GA method, leads to have a valid electromagnetic (EM)-verified post-layout generation and reduces the efforts of any designer in providing ready-to-fabricate layout. For validating our proposed method, we design and optimize MIMO antenna with a bandwidth of 400 MHz in the frequency band 4.1 GHz–4.5 GHz. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG
Low-Loss Paper-Substrate Triple-Band-Frequency Reconfigurable Microstrip Antenna for Sub-7GHz Applications
No full textIn this paper, a low-cost resin-coated commercial-photo-paper substrate is used to design a printed reconfigurable multiband antenna. The two PIN diodes are used mainly to redistribute the surface current that provides reconfigurable properties to the proposed antenna. The antenna size of 40 mm x 40 mm x 0.44 mm with a partial ground, covers wireless and mobile bands ranging from 1.91 GHz to 6.75 GHz. The parametric analysis is performed to achieve optimized design parameters of the antenna. The U-shaped and C-shaped emitters are meant to function at 2.4 GHz and 5.9 GHz, respectively, while the primary emitter is designed to operate at 3.5 GHz. The proposed antenna achieved peak gain and radiation efficiency of 3.4 dBi and 90%, respectively. Simulated and measured results of the reflection coefficient, radiation pattern, gain, and efficiency show that the antenna design is in favorable agreement. Since the proposed antenna achieved wideband (1.91-6.75 GHz) using PIN diode configuration, using this technique the need for numerous electronic components to provide multiband frequency is avoided.Mohammad Alibakhshikenari acknowledges the support from the CONEX-Plus program, funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation program, under the Marie Sklodowska-Curie grant agreement No. 801538. A; Universidad Carlos III de Madrid [801538, RSPD2023R666]; European Union's Horizon 2020 research and innovation program, under the Marie Sklodowska-Curie grant; King Saud University, Riyadh, Saudi ArabiaMohammad Alibakhshikenari acknowledges the support from the CONEX-Plus program, funded by Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation program, under the Marie Sklodowska-Curie grant agreement No. 801538. Ashfaq Ahmad sincerely appreciates funding from Researchers Supporting Project number (RSPD2023R666), King Saud University, Riyadh, Saudi Arabia